Harmonic Mitigation Method with Multi-Resource Participation in Power Distribution Networks

A large number of distributed energy resources (DERs) connected to distribution networks, such as photovoltaic and energy storage systems, can be used to mitigate harmonics in distribution networks because their grid-connected inverters have similar topologies to those of power control devices. In this study, an optimization model is proposed to mitigate the effects of multiple harmonic sources (HSs) using DER inverters with known location, capacity, and operating mode in synergy in a scenario in which the degree of grid-wide harmonic distortion is known. With the optimal harmonic level as the objective function, the DERs are synergistically controlled to mitigate the harmonics of the whole network. To enable the model to be applicable to large networks, a zonal constraint is also considered to constrain the extent of the optimization and control and to improve the solution efficiency and mitigation economics. Finally, the modified IEEE 13 and 123 bus test feeders are used to verify the effectiveness and economy of the proposed method. The case studies show that the proposed method is effective in mitigating harmonics in distribution networks where multiple HSs are present, reducing the mitigation costs while increasing the benefits to DER owners.